Improvement in compasses



A. P. FRESHMAN. Compass.

No. 200,048. Patented Feb. 5,1878.

ATTEST: INVENTOR: Maw Qfi'whmm N. PETERS. PBOTO-UTHOGRAPHER,\IASHINGTQN, 0 C4 UNITED STATES PATENT OFFICE.

ANDREW P. FRESHMAN, OF BELLEVILLE, ILLINOIS, ASSIGNOR OF ON E-HALF HISRIGHT TO GEORGE EISENBERG, OF SAME PLACE.

IMPROVEMENT Specification forming part of Letters Patent No. 200,048,dated February 5, 1878 application filed November 26, 1877.

To all whom it may concern Be it known that I, ANDREW P. Faust:- MAN, ofBelleville, Illinois, have made a new and useful Improvement inCompasses, of which the following is a full, clear, and exactdescription, reference being had to the annexed drawings, making part ofthis specification, in which- Figure 1 is a side elevation of a compasscontaining the improvement, the legs being opened apart; Fig. 2, anelevation, showing the compass closed; Fig. 3, a detail, showing thecompass having caliper-points; and Fig. 4, a cross section taken on theline 00 w of Fig. 2.

Similar letters refer to similar parts.

By means of the present invention theparallelism of the points of thecompass-legs is preserved whatever the angle the legs are opened out to.

The improvement also relates to the provision by which the points of thelegs can be readily replaced or changed.

Referring to the drawings, A represents a compass having my improvement.The legs a a arepivoted to each other at b in the usual manner; but theyare each-(and similarly) made in two sections, a and c and a and 0,jointed, respectively, at cl and d. The legs, at their upper ends, aresimilarly extended a short distance beyond the pivot b. A lever or rod,6, is pivoted at one end, 6 to the extension of the leg at, and at theother end, 6 to an extension, 0 of the section a. A similar rod, f, issimilarly pivoted at f to the leg at, and at f to an extension, 0 of thesection 0. The extensions 0 and o are, respectively, on the outer sidesof the legs a and a.

The various parts being thus arranged, extended, and connected, as thelegs a a are opened apart or closed together the rod 6 causes thesections a and a to turn upon each other, and the rod f causes thesections 0 and a to turn upon each other, and the effect of the combinedmovements is to cause the sections 0 and c to remain parallel with eachother in all positions of the sections a and a,

. for all the parts of the compass are so arranged relatively to' eachother, and so proportioned, that the sections 0 and c are parallel whenthe compass is closed, and that, as the compass is opened, the movementsof the sections 0 and a, respectively, upon the sec tions at and a arejust sufficient to keep the sections 0 and 0 parallel. The relations,respectively, of the pivots e and f to the pivot b affect, of course,the relations of the pivots f and e to the pivots d and 01". As the oneis changed the other must be correspondingly modified.

The lower ends of the sections 0 and 0 may, if desired, be sharpened toconstitute the points of the compass legs. I preferably, however, makethe extreme ends 9 g of the sections detachable. This enables a point tobe renewed with but slight expense. It also enables differently-shapedpoints to be used. In Fig. 3, points h h, shaped suitably for calipers,are shown.

That portion of the improvement first above described is especiallyuseful in connection with such points, for, in making nice measurementswith calipers, it is desirable for the' extreme points to be applied asnearly as is practicable in the line of the diameter being measured. Thekeepingof the sections 0 and 0 parallel enables the points to be thuspresented. v

This improvement is valuable not only in compasses, but also indrafting-instruments, and other tools that consist mainly of two partsor legs pivoted together at one end, and that are used in-measuring.-

I am aware that dividers having what is termed a parallelogram connectedwith a stanchion depending from the head of the dividers have heretoforebeen constructed.

I claim.

The hereindescribed compass, consisting

